HK J Paediatr (new series) 2003;8:126-129

Double Aortic Arch Presenting as Neonatal Stridor

YT CHAN, DKK NG, ASF CHONG, JCS HO

Abstract Stridor is a common complaint in neonates. Association with respiratory distress mandates early flexible bronchoscopic examination of the airway. We report a case of double aortic arch who presented with stridor and respiratory distress. Management of double aortic arch was discussed. Persistence of stridor after surgery and its management was highlighted.

Key words CPAP; Double aortic arch; Newborn; Non-invasive ventilation; Stridor

Introduction Physical examination revealed a normal looking neonate with signs of respiratory distress, i.e. marked subcostal Amongst respiratory symptoms, stridor is a common insucking. Examination of other systems were complaint in a full-term neonate. Congenital cardio-vascular unremarkable. He was found to have cyanosis during anomalies are rare but treatable causes of stridor in the feeding. SpO2 during rest was 100% and during feeding pediatric population. The reported incidence of aortic was 90%. Chest X-radiograph showed bilateral hyper- vascular rings was 0.3-0.6%.1 Double aortic arch was the inflated chest with no other abnormalities. Complete blood most common type of congenital vascular ring anomalies.2,3 picture was normal. The provisional diagnosis was sepsis. We report here the management of a neonate with double The baby was put on nasal continuous positive airway aortic arch that presented as neonatal stridor. pressure (CPAP) support on day 2. His respiratory distress was improved but he still had subcostal insucking. Inspiratory stridor was noticed on day three of life. Case Report Bronchoscopy (Figure 1) showed a short segment tracheomalacia at mid-trachea caused by an extra-mural A newborn was referred to our unit for respiratory pulsatile mass on day 5. Subsequent CT thorax (Figure 2) distress at 1 hour of life. He was a full term baby with birth on the same day showed the pulsatile mass to be double weight of 3.09 Kg. He was born by vaginal delivery. aortic arch. The infant underwent elective operation on day 8 of life. Division of right arch was done, which was complicated by right chylothorax. Chest drain was inserted over right chest Department of Paediatrics, Kwong Wah Hospital, 25 Waterloo for one week and the baby was put on Pregestimil® (Mead Road, Kowloon, Hong Kong, China Johnson, Holland). Right chylothorax resolved after one YT CHAN ( 陳日東 ) MBBS week. The respiratory distress decreased after the operation DKK NG ( 吳國強 ) M Med Sc, FRCP, FHKAM(Paed) JCS HO ( 何誌信 ) MBBS, FRCP, FRCR and he could tolerate slow-rate oral feeding. However, he still had difficult feeding and inspiratory stridor. MRI thorax Department of Radiology, Kwong Wah Hospital, 25 Waterloo (Figure 3) and bronchoscopy (Figure 4) were repeated. Road, Kowloon, Hong Kong, China Persistent tracheomalacia was identified in bronchoscopy. ASF CHONG ( 莊瑞芬 ) MBBS, FRCR, FHKAM(Radiol) Video fluoroscopic swallowing study was normal and the Correspondence to: Dr DKK NG feeding difficulty was likely due to respiratory distress. In Received June 3, 2002 view of the persistent respiratory distress, he was put on Chan et al. 127

Figure 1 Bronchoscopy showed marked Figure 4 Bronchoscopy showed tracheomalacia compression of trachea from 10 o'clock to 4 o'clock (arrow) during inspiration. (arrow) by an extra-mural pulsating mass.

intermitent CPAP. Inspiratory stridor and feeding difficulty improved after the baby was put on intermittent CPAP, two hours during daytime and during sleep. CPAP pressure was

6 cmH2O. He was thriving afterwards. Nocturnal CPAP was tailed off at nine months of age and he was free of symptoms at nine-month of age. During last follow-up at nine-month- old, his body weight was at 80th percentile, compared with body weight at 3rd centile at three-month-age. His feeding was satisfactory and no stridor was detected.

RA: Right arch; LA: Left arch; T: Trachea; E: Esophagus Discussion Figure 2 CT thorax showed double aortic arch causing focal tracheal narrowing. Double aortic arch is due to failure of regression of the right aortic arch. Normally, absorption of the right (posterior) arch takes place between the right subclavian artery and its junction with the descending aorta. The remnant of the right arch becomes the right innominate artery and leaves a left (anterior) arch in normal development, freeing the trachea and esophagus. Failure of this process of absorption in the right arch produces a vascular ring, the esophagus and trachea are completely encircled and compressed, leading to severe respiratory and feeding difficulties. The first successful surgical treatment of a double aortic arch was reported by Dr. Gross in 1945.4 Double aortic arch usually exists as an isolated problem, although the LA: Left arch; T: Trachea; E: Esophagus presence of associated congenital heart disease such as Figure 3 MRI showed mild narrowing of middle and distal tetralogy of Fallot, ventricular septal defect, and trachea. transposition of great arteries were reported.5 128 Double Aortic Arch

Respiratory symptoms at birth or soon after should alert because the prolonged compression of trachea often results the pediatrician to the possibility of vascular ring in tracheomalacia and lung infection.13 Other operative compression. Presenting symptoms included stridor complications include chylothorax, diaphragmatic paresis (100%), persistent cough (75%), chronic dyspnoea (75%), and vocal cords paresis. Complication rate of chylothorax reflex apnoea (60%), recurring respiratory tract infections had been reported to be 2 out of 42 cases.12 In another case (56%) and dysphagia (25%).6 The onset of symptoms from series, 84% of post-operative chylothorax cases responded double aortic arch tended to be earlier than other type of to conservative management. The average duration of lymph vascular rings.3 Majority of patients with double aortic arch leak was 13.7 days.14 have surgical correction before one-year-old, whereas the Surgical division of double aortic arch has been performed average age for congenital vascular ring anomalies (non- without mortality in a case series of 42 patients.12 In another double aortic arch) patients was four-years-old. It was case series of 39 patients with congenital aortic arch suggested that compression of the trachea and esophagus anomalies, two deaths occurred: 1 infant had undergone from double aortic arch was more severe than that with emergency operation for control of hemorrhage from an other types of vascular rings.7 aorto-tracheal fistula due to tracheostomy tube erosion, and Tracheal compression may cause significant morbidity the other had multiple associated congenital heart defects. and mortality.8 CPAP represent5 an important non-invasive Median length of follow-up was 12.5 months, with at least method to relieve airway obstruction before surgery. 97% of survivors completely or nearly completely free of Flexible bronchoscopy would be the first line of symptoms from the vascular ring.15 Another case series also investigation for neonatal stridor. Typical compression of reported symptom-free evolution in most patients over a the esophageus and the trachea was visualized by three to 90 months follow-up period.16 esophagoscopy and bronchoscopy which were indicated CPAP would be a good non-invasive method to relieve for respiratory or feeding difficulties. Nature of extra-mural airway obstruction secondary to the short segment obstruction would be best shown by spiral CT scan, tracheomalacia associated with double aortic arch. This was magnetic resonance imaging (MRI) or color-coded 3D well shown by our patient whose clinical response was echocardiogram reconstruction or angiography. satisfactory with catch-up growth. Angiography confirms the diagnosis by demonstrating the In conclusion, tracheobronchial compression by vascular details of the anomaly. Spiral CT scan and color-coded 3D structures in childhood is uncommon and may be masked echocardiogram reconstruction represent important non- by non-specific respiratory symptoms. Diagnosis required invasive techniques used in evaluation of vascular anomalies a high index of suspicion. Early bronchoscopy is essential of the thoracic aorta and pulmonary arteries in infants and to confirm the vascular compression of trachea. Imaging children.9 One case series showed that angiography, techniques like spiral CT scan or MRI can clearly delineate magnetic resonance imaging, and computed tomography the causative pathologic vascular structures. Surgical were reliable tests and magnetic resonance imaging was treatment is effective and safe. Tracheobronchial malacia found to be the investigation of choice.10 However, magnetic may persist for several months after the operation and CPAP resonance imaging requires a long acquisition time and is is an important tool to relief airway obstruction during the prone to motion artifacts. A case of double aortic arch was pre-operation and post-operation period. reported to be missed on magnetic resonance imaging.11 Hence, spiral computed tomography would be a better choice of non-invasive tool for delineation of nature of References obstruction demonstrated by the flexible bronchoscopy. Surgical division of the vascular ring was indicated in 1. Cordovilla Zurdo G, Cabo Salvador J, Sanz Galeote E, Moreno Granados F, Alvarez Diaz F. Vascular rings of aortic origin: patients with symptoms of airway or esophageal the surgical experience in 43 cases. Rev Esp Cardiol 1994;47: compression. Opening the ring was accomplished by 468-75. dividing the arch and patent ductus or ligamentum arteriosus. 2. Lima JA, Rosenblum BN, Reilly JS, Pennington DG, Nouri- Further dissection along the trachea and esophagus was Moghaddam S. Airway obstruction in aortic arch anomalies. Otolarygol Head Neck Surg 1983;91:605-9. carried out to release any constriction or fibrous band.12 A 3. Nikaido H, Riker WL, Idriss FS. Surgical management of complete release of the constriction by operation may not "vascular rings". Arch Surg 1972;105:327-33. result in the immediate and total resolution of symptoms 4. Gross RE. Surgical relief for tracheal obstruction from a Chan et al. 129

vascular ring. N Engl J Med 1945;233:586-90. Otorhinolaryngol 2000;52:197-201. 5. Binet JP, Longlois J. Aortic arch anomalies in children and 12. Han MT, Hall DG, Manche A, Rittenhouse EA. Scientific infants. J Thorac Cardiovasc Surg 1977;73:248-52. Papers: Double aortic arch causing tracheoesophageal 6. Gormley PK, Colreavy MP, Patil N, Woods AE. Congenital compression. Am J Surg 1993;165:628-31. vascular anomalies and persistent respiratory symptoms in 13. Tucker BL, Takahashi M. Vascular rings. Contemp Surg 1980; children.Int J Pediatr Otorhinolaryngol 1999;51:23-31. 17:11-27. 7. Roesler M, De Leval M, Chrispin A, Stark J. Surgical 14. Nguyen DM, Shum-Tim D, Dobell AR, Tchervenkov CI. The management of vascular ring. Ann Surg 1983;197:139-46. management of chylothorax/chylopericardium following 8. Rivilla F, Utrilla JG, Alvarez F. Surgical Management and pediatric cardiac surgery: a 10-year experience. J Card Surg follow-up of vascular rings. Z Kinderchir 1989;44:199-202. 1995;10:302-8. 9. Katz M, Konen E, Rozenman J, Szeinberg A, Itzchak Y. Spiral 15. Chun K, Colombani PM, Dudgeon DL, Haller JA Jr. Diagnosis CT and 3D image reconstruction of vascular rings and and management of congenital vascular rings: a 22-year associated tracheobronchial anomalies. J Comput Assist Tomogr experience. Ann Thorac Surg 1992;53:597-602; discussion 1995;19:564-8. 602-3. 10. van Son JA, Julsrud PR, Hagler DJ, et al. Imaging strategies 16. Bove T, Demanet H, Casimir G, Viart P, Goldstein JP, Deuvaert for vascular rings. Ann Thorac Surg 1994;57:604-10. FE. Tracheobronchial compression of vascular origin. Review 11. Gustafson LM, Liu JH, Link DT, Strife JL, Cotton RT. Spiral of experience in infants and children. J Cardiovasc Surg (Torino) CT versus MRI in neonatal airway evaluation. Int J Pediatr 2001;42:663-6.